The invention relates to metal melting furnaces to be used in foundry practice.
The present invention may be most advantageously used in furnaces and mixers for producing metal which is fed in pre-set batches directly to continuous casting machines or injection moulding machines. The furnace according to the invention should be preferably used for melting aluminium and aluminium based alloys.
Known in the art are metal melting furnaces having the inner space defined by vertical walls supported by a hearth and bearing a roof. The inner space of the furnace is lined with refractory material, with heaters being accommodated therein above the molten metal level to melt the metal.
In some furnaces, mechanical devices are used for stirring molten metal to even its temperature, and additional heaters are provided to prevent metal from cooling and solidifying at the hearth or in the zone of delivery. The furnace has respective holes for charging the starting metal and for the delivery of finished metal therethrough. The delivery hole is located below the level of molten metal in the furnace and is closed by a pick (metal rod) which is used by the operator to manually control the batch of metal discharged from the furnace with subsequent closing of the hole.
These furnaces have low production output which renders them impractical.
In addition, the metal obtained from such furnaces contains a great quantity of undesired gaseous and solid impurities.
There is also known in the art an arrangement for conveying liquid metal, based on the employment of travelling magnetic field of an inductor (cf. USSR Inventor's Certificate No. 321320). However, this arrangement can only be used at relatively low temperatures for transporting and stirring liquid metals, such as mercury.
The development of mechanical engineering imposes an ever-growing demand for improving the quality and quantity of metal being produced.
Not only do the prior art furnaces fail to meet this demand, but they are unsuitable for automation and do not provide for efficient stirring of metal during its heating.
The above disadvantages adversely affect the operation of the furnaces and render impossible their re-designing.